cpu - Why is Computer Processing Speed Measured in Hertz?

08
2014-07
  • Anthony

    Why is it that processing speed is measured in hertz, and what is a 'good' processing speed?

    Edit: What is it about processing speed that makes cycles per second an appropriate unit of measure. What cycle is being completed?

    • Answers
  • Isaac Rabinovitch

    Hertz is a measure of cyclic change. (It used to be "cycles per second" before they changed it to honor Heinrich Hertz.) In a CPU, Hertz describes clock rate, which is the frequency of a periodic signal that goes out to coordinate what the CPU is doing. The faster the clock, the more instructions the CPU can execute.

    Note that clock speed is only one factor in processor speed. If two processors follow the same architecture, then the one with a higher clock speed will indeed be "faster". But some CPU architectures can burn through more instructions at a given clock speed than others. This has become less and less important as Intel-compatible CPUs drove other architectures off the market. However, the rise of mobile computing has brought the architecture issue forward, as device manufacturers choose the less powerful, but also less battery-draining, ARM architecture.


    • Related Question

    cpu - Why doesn't my computer work at full speed?
  • kubilas

    My motherboard is a Gigabyte GA-8I915PL-G with an Intel Pentium 4 630 3,0 GHz which doesn't run at it's default speed. It's currently at FSB 800, CPU Host 200 and CPU 3000 MHz; but sometimes it runs at FSB 533, CPU Host 133 and CPU 2025 MHz. Sometimes it's even at FSB 75 and CPU 1128 MHz.

    When I configure the default settings in Easy Tune then my computer doesn't work. Sometimes I need to clear the CMOS so I can set the default settings in the BIOS, but that doesn't always help.

    I've updated the BIOS, what else can I do to fix this problem?


    • Related Answers
  • mariom

    Are you sure it's not just saving energy? Put some load with youtube HD videos and look if it doesn't speed up. CPU-Z will report the changes in real time. My core i5 goes from 1200 MHz to 2800 MHz every time it needs more speed.

  • Sathya

    The Pentium 4 630 comes with SpeedStep which downclocks when the load is less to reduce power consumption/heat buildup.

    SpeedStep is a trademark for a series of dynamic frequency scaling technologies, including SpeedStep, SpeedStep II, and SpeedStep III built into some Intel microprocessors that allow the clock speed of the processor to be dynamically changed (to different P-states) by software. This allows the processor to meet the instantaneous performance needs of the operation being performed, while minimizing power draw and heat dissipation. Enhanced Intel SpeedStep is sometimes abbreviated as EIST.

    This is the cause for the variations